Flash lamp



A118- 121 1941 v J, A. M. VAN LIEMPT 2,252,241

FLASH LAMP Filed March 1l, 1938 Patented Aug. `12, 1941 FLASH LAMP Johannes Antonius Maria van Lempt, Eindhoven, Netherlands, assignor, by mesne assignments, to Hartford National Bank and Trust Company, Hartford, Conn., as trustee Application March 11, 1938, Serial No. 195,382

Germany VMarch 30, 1937 6 Claims.

My invention relates to flash lamps, and more particularly to a flasher material for such lamps, i. e., a material which burns to emit the actinic light of the lamp. i Y

For this purpose, it has been proposedto use aluminum or magnesium, the aluminum being preferably used in an extremely thin form, suchl as foil, and the magnesium being even suitable when the material is comparatively thick. However, magnesium has the disadvantage that it is i very diilicult to work, for instance rolled or drawn into a thin foil or a wire, whereas aluminum can readily be worked, more particularly rolled to thin sheets.

The main object of my invention is to produce a flash material that can be mechanically worked even more easily than aluminum, and can be more easily drawn into the form of a wire.

Another object is to produce a material which can be ignited more readily than ahuninum and Whose rate of combustion while emitting actinic light proceeds more rapidly than with aluminum itself.

A further object is to produce a material which develops per unit weight, a larger quantity of light than does pure aluminum or pure magnes1um.

Further objects of the invention will appear as the description progresses.

In accordance with the invention I mix or alloyaluminum with either zinc or cadmium or a mixture thereof-which metals alone burn with hardly any actinic eilect-and vtherebyv obtain flasher materials which are superior to either pure aluminum or pure magnesium. More particularly I u se as the flasher material a band, wire. or foil consisting of an aluminumzinc alloy containing not more than 20 per cent by weight of zinc, or a mixture of aluminum and cadmium containing not more than 80 per cent by weight of cadmium, vor a mixture of aluminum, cadmium and zinc containing not more than 20 per cent by weight of zinc.

In order that my invention may be clearly understood and readily carried into eiect I shall describe the same in more detail with reference provided with an explosive material, for instance a mixture of pulverized aluminum or zirconium and an oxidizing agent such as lead dioxide. Within the container is a flasher material 5 in the form of a clew ofr thin wire having a perimeter of the order of 300'microns or less. The lamp is filled with a gaseous filling such as oxygen or a gas containing oxygen.

In accordance with the invention the flasher material 5 consists of an aluminum-zinc alloy containing not more than 20% by weight of zinc, a mixture of aluminum and cadmium containing not more than 80% by weight of cadmium, or a-mixture of aluminum, cadmium and zinc containing not more than 20% by weight of zinc.

Above I have referred to both alloys and mixtures, and to clarify this it should be noted that aluminum and cadmium valloy only partially inthe literal meaning of the term. However, when there is more than 5% cadmium, the nonalloying cadmium particles can be suiilciently finely distributed throughout the molten aluminum-cadmium alloy by stirring vigorously, so that pseudo-alloys containing substantially more than 5% cadmium, for instance 60%, can be obtained. Such pseudo-alloys can be drawn into 'a wire as readily as the ordinary alloys. I have found 'that an aluminum-cadmium alloy containing not more than 5% cadmium burns more readily than does pure aluminum, and has a flash-time which, for the same thickness of' wire, is not much shorter than that of aluminum itself. However, the above-mentioned pseudoalloys have a much shorter flash-time with an equal quantity of emitted light, and this time is even shorter than that of aluminum and that of aluminum-zinc alloys containing not more than 20% by weight of zinc.

The invention may also be carried into effect when using aluminum-cadmium-zinc mixtures containing not more than 20% by weight of zinc and whose properties correspond to those of the alloys or mixtures referred to above.

to the accompanying drawing` in which the single figure is a partly-sectionized side view of a flash lamp embodying the invention.

The ash lamp illustrated in the drawing comprises a container I of light-transmitting material such as glass having a press 2. Supported frompress 2 by means of`two supportlead 3 is an igniter or primer such as a lament I have found that the following specic alloys and mixtures give very good results: Aluminumzinc containing 17% by weight of zinc, aluminum-cadmium containing '40% by weight of v cadmium and aluminum-zinc-cadmium containing 6% by weight of zinc and 9% by weight of cadmium.

The flasher materials according to the invention have the advantage over pure aluminum that the flash time, i. e., the time required for This curve oi' the aluminum and of the alloys or mixtures according to the invention. In addition I have found that the Bash-time 'of the asher materials of the present invention becomes shorter as the zinc content increases, and as the cadmium content increases to about 80%.

Furthermore, the asher material of the invention can bereadily drawn into a very thin wire. which is of great advantage. More particularly the iiasher material is preferably used in the form of a thin wire or band, instead of a foil, because drawing the material into a thin 2,252,241 can be determined by observing the light-time desire the appended claims to be kconstrued as broadly as permissible in view of the prior art.

What I claim is:

1. In a photo-Hash lamp, a asher material consisting of an alloy of aluminium, zinc, and cadmium in the proportion of about 6% by Weight of zinc, of about 9% by weight of cad- I- mium, and the remainder aluminium.

wire or band is, from a mechanical viewpoint, A

much easier and cheaper than rolling it intoV thin foil.

Although aluminum-magnesium alloys containing more than 85% or less than 13% of magnesium are entirely satisfactory asilasher materials and can be readily drawnl into thin wires, the asher material according to the in vention has the additional advantage over such alloys that when in the form of wire the quantityof light developed per unit length is about 10% greater.

The word alloy asused inthe claims is tov be understood to include both a true alloy as well as a pseudo-alloy or mixture.

While I have described my invention in connection with dash-lamps in which the asher material is in-the form of a wire, the material may be in other forms such as a foil or a band. Therefore I do not Wish mbe-'limited to the speciiic--applications and examples described but 2. In a photo-flash lamp, a flasher material consisting of an alloy of aluminium and zinc in the proportion of about 1%- to 20% by weight of zinc and the remainder aluminium.

'3. In a photo-flash lamp, a flasher material consisting of an alloy of aluminium and zinc in the proportion ofabout 17% by weight of zinc consisting of an alloy of aluminum and at least one of the metals zinc and cadmium in the proportion of 99 to 20% by weight of aluminuml and 1 to 80% by weight of zinc and cadmium, the' Zinc content lyingbetween 0 and 20% by Weight.

JOHANNES ANTONIUS MARIA VAN LIEMIPT. 

